This invention relates to an adjustable end-dogging log carriage for passing random-length logs through log-processing equipment, and more particularly to such a log carriage having more than two dogs for supportably engaging the ends of the log.
Conventional end-dogging log carriage systems typically employ two dogs which clamp or "dog" the log by its longitudinal extremities and then pass the rigidly clamped log through log processing equipment such as chippers and bandsaws. If the logs to be processed are all of the same length, the two dogs are arranged at fixed distance from each other, if however, the logs to be processed are of random length, the log carriage must be extensible to accommodate the varying length of the logs. This is customarily accomplished by providing a log carriage with a movable dog which is movable with respect to the other fixed dog and requiring the log carriage to return to a "backstand" position which places the fixed dog at a predesignated position commonly called the "zero log line." The fixed dog remains stationary at the zero log line while the particular log to be processed is manipulated by other log-processing equipment so that one of its ends is also proximate at the zero log line facing the fixed dog and the movable dog is moved along the supporting carriage track until it is in the proper position to dog the other end of the log. Actual dogging is accomplished by urging the movable dog toward the fixed dog until the log is securely clamped between them and ready to be processed.
Adjustment of the log carriage to accommodate different length logs increases the amount of time required to process each log, thereby affecting the log "throughput" of the entire sawmill. For example, if an eight-foot log is processed immediately after a 24-foot log, the movable dog must move approximately 16 feet toward the fixed dog in order to be in position to clamp the log. Other related disadvantages are the additional energy requirements and increased wear on the carriage components which are caused by the carriage adjustment travel.